Process for the manufacture of phenol from aromatic hydrocarbon halides



W. RITTLER PROCESS FOR THE MANUFACTURE OF PHENOLS Filed Sept. 50, 1931 New. 2, l933.

FROM AROMATIC HYDROCARBON HALIDEs ENVENTOR BY ATTORNEy Patented Nov. 21, 1933 UNITED STATES PROCESS FOR THE MANUFACTURE OF' PHENOL FROM AROMATIC HYDROCAB- BON HALIDES Willy Rittler, Oberloessnitz, near Dresden, Gex'-r many, assignor to Chemische Fabrik von Heyden, A. G., Radebeul, near Dresden, Germany, a corporation of Germany Application September 36, 1931', Serial 565,942, and in Germany April 16, 1930 19 Claims. (Cl. 26o-154) This invention relates to a process for the manufacture of phenols and it particularly relates to a process for manufacturing such phenols from hvdrocarbon-halides by acting upon the same with water vapor in the presence of catalysts, whereby the halogen of the hydrocarbonhalides is split off and substituted by a hydroxyl group, hydrochloric acid and a phenol being formed by this reaction.

It is known that the hydrolysis of chlorbenzol by water in the vapor phase is accelerated by catalysts, such as aluminum oxide, thorium oxide, zirconium oxide, blue tungstic oxide etc., and that also the yield of phenol is increased.

It also has been stated that the best yields of phenol, approximating 75%, are obtained by using active silica-gel as a catalyst.

I have now found the fact, which is most important for the economical development of this type of processes, that with the considerably cheaper, naturally occurring bleaching earths as they are used for the bleaching of oils, phenol may be obtained in very good yields at temperatures from approximately 350-60 C. With my process an addition of activators, for instance of metals such as copper, nickel etc., may be of advantage.

Bleaching earths belong to the group of clays and are found in nature all over the world as the conversion products of feldspat, they are aluminum-hydrosilicates and answer the general formula Al(OH)3.nH2O.mSiO2. They are mostly used for the bleaching and clarification of aqueous solutions and of organic liquids, such as oils and fats.

This bleaching power is an inherent property of these clays, but it is known that this particular effect can be increased by the action of a strong acid on the clays.

In Germany a great number of such bleaching earths are sold on the market, mostly under a tradename, such as Tonsil, Terrana, Clarit, Alsil, Sihydrol, Isarit, Frankonit, Silica R, Leukorit, Albanit, etc.

The well known American clays, such a fullers earth, Florida earth, bentonite, answer the purposes of my new process, also the various clays found in England, Japan, etc.

The increase of the bleaching power of the natural bleaching earths may be effected in any suitable manner, for instance, by heating a mixture ci clay and acid, preferably strong acids, such as hydrochloric acid and sulfuric acid, with steam for several hours in a suitable digester provided 55 with an agitator. After the desired conversion has been accomplished, the mixture is allowed to settle, whereupon the residue is filtered through presses and thoroughly washed with water. The residue is then dried and disintegrated to a very ne powder. This particular treatment of the clays for the increase of their bleaching effect, is known and this particular step is therefore not claimed as a part of the present invention.

For application as catalyzers the bleaching earths are suitably formed into balls, cylinders, cones, shells, or lumps, so that the gases in passing over them in the catalyzer-tube have hardly any or only very little resistance.

For the better understanding of my new invention I am going to describe how I may operate to put the same into eiect and as an example I choose to describe the said operation in connection with the transformation of chlor-benzol into phenol, emphasizing, however, that the operation proceeds equally well with Chlor-toluene or other halogen compounds of the homologues of benzol.

For the illustration of the various steps of the process, reference is had to the accompanying drawing which in a rather diagrammatic way shows a vertical sectional View of an apparatus which I found very suitable for carrying my invention into effect.

In a general way I may say that the chlorbenzol is vaporized in a still and that these vapors, mixed with water vapor, are conducted over bleaching earth, for instance Tonsil, which is brought into a suitable shape and is heated to a temperature of about 500 C. From the oil'- going vapors the phenol and the hydrochloric acid gas are separated by having them absorbed by an alkali-metal hydroxide, while undecomposed chlor-benzol is condensed and returned to the process. After all the chlor-benzol has been transformed, the phenol is recovered in any of the well known ways. The yield of pure phenol is about 75%. An addition of metals, such as copper, nickel, etc. to the catalyst, may be an advantage.

Referring to the accompanying drawing, the numeral 1 denotes a kettle 1 which may be heated by direct heat or by means of a steam coil (not shown). A catalyzer tube 2 is mounted on top of and communicates with kettle 1, the tube 2 containing the catalyst 3, arranged on a suitable grate 4, secured at its bottom, up to nearly its rim, the catalyst being in the form of balls or tablets. The tube 2 is connected with the condensing chamber 5 by' a neck 6, in the wider part of which a thermometer tube 10 is inserted to reach deeply into the catalyst 3 so as to allow measuring its temperature within approximately the middle of its body, the temperature being ascertained either by means of an electric or mercury thermometer (not shown).

The condensing chamber 5 has an outlet 5a which terminates within and shortly below the rim of the bell 7 of a funnel 8 entering into and terminating shortly above the bottom of the kettle 1.

The condensing chamber 5 is provided with a coil or a system of tubes cooled by running water (not shown).

The catalyzer tube 2 is surrounded by an electric heating arrangement 9 suitably of cylindrical shape, the resistance wire of said arrangement being connected with the bus-bars of a source of electric energy (not shown).

The apparatus described above may be made of various materials, it should of course be a material which is not effected by an alkali metal hydroxide solution, such as sodium hydroxide solution. Furthermore, the catalyzer tube 2, the neck 6 and the condensing chamber 5, must be made of a material which is resistant to the vapors of chlor-benzol, phenol, water vapor and hydro-chloric acid gas. If I use,. for instance, copper, or a copper alloy, the effect of the vapors on the same is relatively small. The copper,

however, particularly if the catalyzer tube 2 is made thereof, exerts a favorable effect upon the process and I may thus obtain yields of phenol ranging from 90-100%.

Instead of using the activators, the catalyst 3, as described above, I may embody the catalytically acting metals, or metallic compounds, the so called activators, in any suitable way into the acid bleaching earths, acting as catalysts.

The operation of the process by means of the apparatus described above, is about as follows:

I fill into the kettle 1, for instance 112.5 kilo of chlor-benzol and 950 kilo of 10% NaOH solution and heat it by direct heat, for instance a gas burner (not shown) in order to bring the mixture of chlor-benzol and sodium hydroxide solution to boiling. In the meantime, I also turn on the electric current to heat the catalyst 3, consisting of aforesaid tonsil, to a temperature of 500 C. so that this temperature is reached when the mixture of chlor-benzol and sodium hydroxide starts to boil. When this point is reached, the vapors of chlor-benzol and water ascend into the catalyzer tube 2 and the catalyst 3 therein causes the water vapor to act on the chlor-benzol, generating vapors of phenol and hydrochloric acid.

These vapors travel from the catalyzer tube 2 into the neck 6 and pass into the condenser chamber 5 where they are condensed, the condensate being discharged through the outlet 5a into the bell 7 of the funnel 8. The condensate consists of unchanged chlor-benzol, phenol and hydrochloric acid and when this condensate enters through funnel 8 into the mixture of chlorbenzol and sodium hydroxide contained in kettle 1, the phenol and the hydrochloric acid are neutralized, whereas the unde-composed chlor-benzol is vaporized again; this cycle is repeated until all the Chlor-benzol is de-composed. In order to bring about a complete transformation of all the chlor-benzol charged into the kettle 1, the presence of an excess of sodium hydroxide in the kettle 1 is necessary.

The kettle 1 ultimately contains no chlorzenzol, but only an aqueous solution of phenolsodium and sodium chloride, from which in the well known way the generated phenol may be separated in any of the well known ways, for instance by acidulating aforesaid aqueous solution, and extracting the phenol from said solution, or distilling it from its residue, obtained after evaporating the water; likewise the separation of the generated phenol from the nontransformed chlorbenzol and the generated hydrochloric acid may also be performed by distilling off the phenol, or by any other well known manner, which may suggest itself under the csircumstances of any given situation.

What I claim is:

1. The process for manufacturing phenols from aromatic hydrocarbon halides, said process comprising conducting, at a temperature of from approximately 350-600" C., the hydrocarbon halides with water vapor over minerals containing aluminum hydrosilicate.

2. The process for manufacturing phenols from aromatic hydrocarbon halides, said process comprising conducting, at a temperature of from approximately S50-600 C., the hydrocarbon halides with water vapor over minerals containing aluminum-hydrosilicate and an activating substance.

3. The process for manufacturing phenols from aromatic hydrocarbon halides, said process consisting in conducting, at a, temperature of from approximately 350-600 C., aromatic hydrocarbon halides with water vapor over minerals containing aluminum-hydrosilicate, separating the generated phenol and hydrochloric acid from the reaction products, passing the undecomposed hydrocarbon halide again with water vapor over the aforesaid minerals, separating again the phenol and hydrochloric acid from the reaction products, and repeating this cycle of steps until all the hydrocarbon halide is transformed into phenol.

4. The process for manufacturing phenols from aromatic hydrocarbon halides, said process consisting in conducting, at a temperature of from approximately 350-600 C., aromatic hydrocarbon halides with water vapor over minerals containing aluminum-hydrosilicate and an activating substance, separating the generated phenol and hydrochloric acid from the reaction products, passing the unde-composed hydrocarbon halide again with water vapor over the aforesaid minerals, separating again the phenol and hydrochloric acid from the reaction products, and repeating this cycle of steps until all the hydrocarbon halide is transformed into phenol.

5. The process for manufacturing phenols from aromatic hydrocarbon halides, said process consisting in boiling a mixture of an aromatic hydrocarbon halide and of an aqueous solution of an alkali metal hydroxide, thereby generating vapors of the said hydrocarbon halide and of water, conducting the vapors of the hydrocarbon halide and of water over catalytically act/ive acid earths in the presence of activating substances, both the acid earths and the activators being maintained at a temperature of from S50-600 C., condensing the reaction products, consisting of unchanged hydrocarbon halide, phenol and hydrochloric acid gas, introducing the condensate of said reaction products into the aforesaid mixture of hydrocarbon halide and of the aqueous solution of the alkali metal hydroxide, thereby neutralizing the phenol and the hydrochloric acid, and repeating the cycle of aforesaid steps with the unchanged hydrocarbon 6. The process for manufacturing phenol from Chlor-benzol, comprising conducting the vapors of chlor-benzol and of water, at a temperature of from approximately 350-600 C., over minerals containing aluminum-hydrosilicate.

7. The process for manufacturing phenol from chlor-benzol, comprising conducting the vapors of Chlor-benzol and of water, at a temperature of from approximately 35o-600 C., over minerals containing aluminum-hydrosilicate and an activating substance.

8. The process for manufacturing phenol from chlor-benzol, consisting in conducting the vapors of chlor-benzol and of water, at a temperature of from approximately 350-600" C., over minerals containing aluminum-hydrosilicate, thereby generating phenol and hydrochloric acid, separating the phenol and hydrochloric acid from the reaction products, conducting the unchanged chlorphenol again over the aforesaid minerals and repeating the cycle or steps until all the chlorbenzol is transformed into phenol.

9. The process for manufacturingphenol from chlor-benzol, consisting in conducting the vapors of chlor-benzcl and of Water, at a temperature of from approximately S50-600 C., over minerals containing aluminum-hydrosilicate and an activating substance, thereby generating phenol and hydrochloric acid, separating the phenol and hydrochloric acid from the reaction products, conducting the unchanged chier-phenol again over the aforesaid minerals and repeating the cycle of steps until all the chlor-benzol is transformed into phenol.

10. The process as described by claim 6, comprising conducting the vapors of chlor-benzcl and of Water over minerals containing aluminumhydrosilicate and copper.

11. 'Ihe process as described by claim 8, comprising conducting the vapors of chlor-benzol and of water over minerals containing aluminumhydrosilicate and copper.

12. The process for manufacturing phenol from chlor-benzol, said process consisting in boiling a mixture of chlor-benzol and of an aqueous solution of an alkali metal hydroxide thereby generating vapors of the said chlor-benzol and of Water, passing the vapors of chlor-benzol and of the water over minerals containing aluminumhydrosilicate maintained at a temperature of from eov 'the same is completely transformed into phenol.

' 35o-600 C. over a bleaching earth consisting of a approximately 3BG-600 C., condensing the reaction products consisting of unchanged chlor-benzol, phenol and hydrochloric acid gas, introducing the condensate of said reaction products into the aforesaid mixture of chlor-benzol and of the aqueous solution of the alkali metal hydroxide, thereby neutralizing the phenol and the hydrochloric acid, and repeating the cycle of aforesaid steps with the unchanged chlor-benzol until 13. The process for manufacturing phenol from chlorbenzol, comprising conducting the vapors of chlorbenzol and of water at approximately 350-600 C. over bleaching earths consisting of a natural clay having been treated with a strong inorganic acid.

14. The process for manufacturing phenol from chlor-benzol, comprising conducting the vapors of chlor-benzol and of Water at approximately natural clay, having been treated with a strong inorganic acid, and of an activating substance.

l5. The process for manufacturing phenol from chlor-benzol, comprising-conducting the vapors of chlor-benzol and of water at approximately 35o-600 C. over a bleaching earth consisting of a natural clay, having been treated with strong inorganic acid, and of copper'.

16. The process for manufacturing phenol from chlor-benzol, comprising conducting the vapors of chlor-benzol and of water at substantially 350- 600 C. over fullers earth.

17. The process for manufacturing phenol from chlor-benzol, comprising conducting the vapors of chlor-benzol and of water at substantially 350- 600 C. over fullers earth in the presence of activating substances.

18. The process for manufacturing phenol from chlor-benzol, comprising conducting the vapors' of chlor-benzol and of water at substantially 350- 600 C. over fullers earth in the presence of copper.` 'l

19. The process for manufacturing phenols from aromatic hydrocarbon halides, said process comprising conducting, at a temperature of from approximately S50-600 C., the hydrocarbon halides with water vapor over minerals containing aluminum-hydrosilicate and having been treated with a strong inorganic acid.

WILLY RI'I'ILER. 

